1. Field of the Invention
This invention is in the field of solar liquid heating devices and more particularly relates to passive concentrating solar collectors for heating water for domestic and industrial use.
2. Description of the Prior Art
Solar collectors are broadly divided into active and passive systems. Active systems track the sun from sunrise to sunset while the passive systems do not include a tracking system. Passive systems can be further divided into flat plate and concentrating collectors. In concentrating solar collectors, radiant electromagnetic energy, primarily in the visible spectrum, is reflected from an area that is substantially larger than the area of the energy absorbing collector element, or tube. In other words, the radiant energy from the sun over a reasonably large area is concentrated on the smaller area of the collector. The solar collector of this invention is a passive concentrating solar collector.
The solar collecting art is highly developed so that most of the technical problems associated with solar collectors are known. Such problems include maximizing the amount of solar radiation concentrated on the collector element, minimizing the losses of energy from the collector element by convection and radiation where such back radiation is primarily in the infrared spectrum, and increasing the rate of flow of energy into the water in the collector element or, stated another way, minimizing the thermal impedance between that portion of the element that absorbs the solar energy and the water contained therein. The problem is now to optimize the solutions of these technical problems while minimizing the cost of manufacturing, of installation and of maintenance of such solar collectors.